Primary cell



Jan. 11, 1955 1. c. BLAKE 2,699,460

PRIMARY CELL Filed Sept. 22, 1953 IN V EN TOR.

[15?22 a filaff/ United States Patent PRIMARY CELL Application September 22, 1953, Serial No. 381,687

.4 Claims. (Cl. 136-111) This invention relates to improvements in primary cells in which the depolarizing cathode contains cuprous chloride as an essential ingredient. Particularly, the invention relates to a cell of the character described in which a member is provided which restricts the movement of cuprous ions from the cuprous chloride cathode to the anode. More specifically it relates to the provision of a cuprous ion restricter member which is comprised of parchment paper arranged across the path of ions between the cathode and the anode.

An important application of the present invention is with a primary cell of the flat type in which the elements are thin and fiat and are arranged in stacked, sandwichlike relation. It has been experienced in the use of cells of the character described, having a cuprous chloride cathode, that overheating and a useless dissipation of energy take place during discharge of the cells. Such action is more pronounced in. flat cells where the cathode and anode are physically in close proximity to each other. Investigation of the problem has disclosed that a substantial action takes place wherein cuprous cations migrate from the cathode and deposit onthe anode. This action is different from the well known action within a primary cell in accordance with which cations travel to the cathode during the current-producing operation of the cell. It has been found that a substantial quantity of cuprous cations, ionized from the cathode, migrate from the vicinity of the cathode to the anode, and a deposition of copper on the anode takes place. As a result, local couples are created at the anode, and a local action ensues which is one of the major causes of overheating and the useless dissipation of energy in a cell of the character described. The present invention is addressed to the solution of this problem.

It is one of the objects of this invention to provide a construction for primary cells of the character described wherein deleterious migrations of cuprous ions to the anode is prevented.

It is another object to provide an improved primary cell of the character described in which passage of cuprous ions to the anode is prevented while at the same time the free fiow of ions required for the useful operation of the cell takes place without restriction.

Another object is to provide an ion restricter which is flexible and adapts itself to the designed shape of the cell and which is economical and has qualities which facilitate simplicity in manufacture.

Other objects will be apparent from the following description in which an embodiment of the invention is described.

Briefly, the objects are accomplished by interposing across the path of the ions between the cathode and the anode a restricter member composed of a sheet of parchment paper.

In the drawing,

Fig. 1 is an enlarged sectional elevation, taken along line 1-1 of Fig. 2, of a primary cell representing an embodiment of the invention, and

Fig. 2 is a sectional view along line 22 of Fig. l.

The specific embodiment which is described and illustrated herein is a deferred-action fiat cell which is composed of thin, flat, sheet-form elements in parallel juxtaposed, sandwich-like arrangement. The cell does not contain electrolyte as made but the cell elements are exposed to the surrounding space whereby the cell is adapted to be rendered operative when desired by being brought 2,699,460 Patented Jan. 11, 1955 into contact with activating liquid. The specific embodiment is described and illustrated by way of example and not of limitation, and the cell may be of a physical form other than that disclosed and it may be of other than the deferred-action type. For example, it may contain an electrolyte initially when manufactured. .1

The primary cell is comprised of a plurality of juxtaposed thin cell elements arranged in a stacked laminar-like relationship. By way of illustration and not of limitation, said elements comprise, from left to right in Figs. 1 and 2, the positive terminal 11 composed of copper, the depolarizing cathode 12 containing cuprous chloride as the essential element, the ion restricter mem ber 13 composed of a sheet of parchment paper, the electrolyte-receptive non-conductive element 14 of suitable bibulous substance such as blotting paper, the anode 15 composed of magnesium and the negative terminal 16 of copper. The terminal 16 is mechanically joined and electrically connected to the anode 15 in any suitable manner, preferably by the pressure-welding procedure known as metal cladding. Cladding procedures are well known and will not be described herein. The cladded element 16 is welded to the anode 15 throughout the con- [acting area of the two elements. The thickness of the elements is exaggerated in the drawing for purposes of clearness, the elements 11 and 16 in practice usually being of foil thickness. The broad exterior surfaces of terminals 11 and 16 form the faces of the cell. All of the elements are flexible. The restricter member 13 will be described in detail hereinafter.

While the composition of the depolarizing cathode containing cuprous chloride is not critical, a suitable compositionis a mixture ofcuprous chloride, graphite, sodium chloride, a wetting agent such as sodium alkyl naphthalene sulfonate, and a binder such as a paste of polystyrene initially containing a solvent such as carbon tetrachloride which evaporates after the composition has been shaped into the body 12.

In the group which has been described, the cell elements are maintained in parallel juxtaposed sandwich-like relationship by binding them together under pressure with a substantially electrolyte-impervious, dielectric tape 20. The tape covers the two opposite long edges of the group, made up of the side edges of the cell elements, and the marginal portions of the cell faces, leaving exposed to the surrounding space the major portions of the cell faces and the two remaining edges of the group of cell elements. The enclosed long edges are designated as the side edges and the unenclosed edges are designated as the ends of the cell. The tape 20 has a coating of pressure-sensitive adhesive upon its interior surface whereby a firm adhesive attachment is made between the contacting surfaces of the cell elements and the tape. Each cell is an integral unit.

The cell is activated by bringing the unenclosed ends of the cell elements in contact with the activating liquid. The electrolyte-receptive elements, including the element 14 and the cathode l2, absorb and become permeated with said activating liquid. A dilute aqueous solution of sodium chloride is a suitable activating liquid, an example being a water solution containing 5 percent of NaCl, based on the weight of the solution. After it has been absorbed into the cell as described, the activating liquid becomes the electrolyte of the cell, and the mechanical arrangement of cell elements in the manner described places the depolarizing cathode 12 and the anode 15 in access relation to the electrolyte.

The ion restricter member 13 is arranged across the path of ions between the cathode 12 and the anode 15. Physically, it is interposed between said cathode and anode. It is comprised of a sheet of parchment paper, commonly known as vegetable parchment. The thickness of the sheet 13 is not critical, a thickness of .002 inch being quite suitable. Such a sheet possesses the inherent property of arresting the flow of cuprous ions from the cathode to the anode. At the same time, it possesses the inherent property of permeability with respect to the flow of ions to the cathode which occurs as a part of the useful current-producing electrolytic action of the cell, whereby the efficiency of the cell is not appreciably affected by its presence. The sheet 13has the additional inherent property-of mechanical flexibility. Fromthe structural and manufacturing standpoints, the sheet 13 possesses the additional advantages that it'is simple and economical.

The.;.reason:.:for. the.:.action initihibiting the .flow of cuprousions to the anode is unknown but it .is. believed thattthe parchment-paper creates a :physical resistance .to the :ioniciiow of :the-cuprousions within.:the CCllzWhiCh is'. sufficient that saidzions.areeprevented fromniigrating from the planar spaee adjacent tozthexdepolarizingzcathodelthrough thelelectrolyteto the anode.

The.:cell.;of .the.presentiinventioniis intendedizfor use in a multiple C6111 battery iniwhichuanumber. of the cells are placedcin side-.by-side .juxtaposed;relation withthe broad exposed surface .of .the'positive terminal 11 of .one cell inimechanical andelectrical .contact .with;the broad 'exposed surfaceof thernegative terminal 16 of the adjacent cell; The -:cells arebound together. under pressure in a sandwich-like arrangement byimeans of .tape or other suitable means.

When a plurality of cells as shownin Figs. 1 and2 are assembled under compression into a battery the elements compress and flex to accommodate the .tape 20 along the margins :of thecellfaces, and the restricter member .13 also undergoes a flexing. The parchment paper readily undergoessuch flexing. Also,: it is easily cut to fit the size and shape requirements of any cell.

While only a single embodimentxof the invention. has been describedand-illustrated, modifications thereof will be apparent to those skilled inthe art. For example, the shapewand typeoffthe cell, and of the parts thereof, the type of cell systennand the material of the elements may be varied without departingfrom the spirit of the invention. As an example of a change of.material,.zinc may be used inplace'of magnesium for the anode.

Invention. is claimed as follows:v

1. In a primarycell .havingrananode and adepolariz.

. 4' ing cathode containing cuprous chloride as an essential ingredient, a restricter member for arresting migration of cuprous ions from the cathode to the anode comprising a sheet of parchment paper across the path of ions between said cathode and said anode.

2. In a primary cell comprising a plurality of flat cell elements in juxtaposed laminar relationship including an anode and a depolarizing cathode containing cuprous chloride as an essential ingredient, a restricter member forarresting migration of cuprous ions from the cathode to the anode comprising a sheet of parchmentpaper interposed between said cathode and said anode.

3. In a primary cell comprising a plurality of fiat'cell elements in juxtaposedlaminar relationship including an anode and a depolarizing cathode containing cuprous chloride as an=essential ingredient, a..restricter member for arresting migration of cuprous ions from the cathode to the anode comprising a flexible sheet of parchment paper. interposed .b'etween said cathode iandtsaidanode.

4. A primary cell. having ::an .anode, a depolarizing cathode containingcuprous chloride as an essential. .ingredient, and .an electrolyte between said anode and cathode,.said electrolyte .occupying a space of substantial width in the direction of the flow of ions between'said anode and cathode, and a restrictor .memberfor arresting migrationof.cuprousions from the cathode to the anode comprising a sheet of parchment .paperv across the path of ions between said cathode and said anode, .said-restrictor member-occupying only a portion of theiforementionedwidth of electrolyte space.

Laszcynski ..Nov. 25, 1902 Ellis: Oct. 13, 1953 

